Vehicle doors installed in vehicles have in many cases a multi-part window frame, which forms a support structure for receiving a vertically displaceable glass pane (drop window). Vehicle doors with a closed window frame can be manufactured substantially in two construction types. A conventional construction type is the two-shell system, in which the glass pane is arranged between two sheet metal parts forming the window frame and is guided within a U-shaped channel. The outer side of the vehicle frame is formed by the corresponding sheet metal part. Another conventional, more modern construction type is the so-called “frame under glass concept”, in which the upper part of the vehicle frame is typically embodied in two parts and provides the mount for a U-shaped channel. This U-shaped channel is usually formed by a plastic part, for example by a decorative cover. The U-shaped channel receives at the same time a sealing part, which seals and guides the glass pane. Consequently, in contrast to the conventional two-shell system, the outer side of the vehicle door is formed by a plastic part in the region of the B-pillar of the window frame.
Irrespective of the construction type used, the vehicle door which is mounted on the vehicle body, for example aside door of the vehicle, includes a planar base section, on the upper side of which a window frame is formed. Here, the window frame surrounds an opening which serves to receive the vertically displaceable glass pane. The window frame includes a front, approximately vertically running vertical strut, a rear, likewise approximately vertical strut and an upper transverse strut connecting the two vertical struts to one another. In the installed state, the rear vertical strut of the front side door and the front vertical strut of the rear side door typically extend along a support pillar, in particular center pillar (B-pillar), of the vehicle body. In the frame under glass concept, it is usual to mount the decorative cover in the region of the vertical struts, in order to give an attractive appearance to the vehicle door, in addition to receiving the sealing part.
Usually, decorative covers are fastened at three fastening points on the window frame. All three fastening points may be arranged in the region of the U-shaped channel. Alternately, a first fastening point is provided at the upper end of the window frame and two fastening points in the channel region. In this way, the decorative cover can advantageously be positioned at the upper end very precisely and largely free of play in particular in relation to adjacent components, which leads to a qualitatively high-grade aesthetic impression.
DE 10 2010 050 959 A1 discloses a type of fastening of the decorative cover in the region of the guide and the seal of the glass pane is described. Here, the decorative cover has a formed-on screw boss or an insert part such as a sheet metal nut, which cooperate with a screw which is screwed from the inner side of the vehicle into the formed-on screw boss or the insert part. In the case of the formed-on screw boss, the screw which is used is usually self-tapping.
DE 10 2009 026 070 A1 discloses a possibility for fastening the decorative cover in the region of the guide and the seal of the glass pane is also described. Here, the decorative cover has a U-shaped holding cross-piece, into which a projection of the window frame must be introduced. The decorative cover is then turned until the decorative cover lies flat against the window frame. The decorative cover is then fastened to the window frame by means of a plug-in spreader element. The spreader element can already be introduced into the decorative strip before the actual fastening process, so that during the fastening process it is already pre-positioned, which is advantageous from a logistical point of view. In addition, during the mounting, the spreader element does not have to be positioned and does not have to be screwed, but rather it only needs to be pressed in, so that no screwdriver is necessary, which is an advantage with regard to production.
In both cases, the screws of the fastening points, arranged in the channel region, project into cavities which are formed by the window frame. In the second embodiment, however, the following circumstance is to be taken into consideration: In the transition of the window frame from the hollow struts into the transverse strut, the window frame does not form a cavity into which a screw could project. Consequently, the decorative cover in this region is fastened up to now by a screw originating from the inner side of the window frame, the screw head of which is visible from the interior of the vehicle, which, however, does not make a positive impression from an aesthetic and qualitative point of view and, in addition, makes a screwing-in process necessary, which is time-intensive.